Greenbrier Companies INC (GBX) SEC Filings — 2026 1 SEC filing for Greenbrier Companies INC (GBX) in 2026. FilingsGreenbrier Companies Files Q1 2026 10-Q Report — 10-Q · Apr 7, 2026 ExploreAll GBX Filings · GBX 2025 · All 2026 Filings